drivers/w1/masters/w1-gpio.c

   1 /*
   2  * w1-gpio - GPIO w1 bus master driver
   3  *
   4  * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2
   8  * as published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/slab.h>
  15 #include <linux/w1-gpio.h>
  16 #include <linux/gpio.h>
  17 #include <linux/of_platform.h>
  18 #include <linux/of_gpio.h>
  19 #include <linux/err.h>
  20 #include <linux/of.h>
  21 #include <linux/delay.h>
  22
  23 #include "../w1.h"
  24 #include "../w1_int.h"
  25
  26 static u8 w1_gpio_set_pullup(void *data, int delay)
  27 {
  28         struct w1_gpio_platform_data *pdata = data;
  29
  30         if (delay) {
  31                 pdata->pullup_duration = delay;
  32         } else {
  33                 if (pdata->pullup_duration) {
  34                         gpio_direction_output(pdata->pin, 1);
  35
  36                         msleep(pdata->pullup_duration);
  37
  38                         gpio_direction_input(pdata->pin);
  39                 }
  40                 pdata->pullup_duration = 0;
  41         }
  42
  43         return 0;
  44 }
  45
  46 static void w1_gpio_write_bit_dir(void *data, u8 bit)
  47 {
  48         struct w1_gpio_platform_data *pdata = data;
  49
  50         if (bit)
  51                 gpio_direction_input(pdata->pin);
  52         else
  53                 gpio_direction_output(pdata->pin, 0);
  54 }
  55
  56 static void w1_gpio_write_bit_val(void *data, u8 bit)
  57 {
  58         struct w1_gpio_platform_data *pdata = data;
  59
  60         gpio_set_value(pdata->pin, bit);
  61 }
  62
  63 static u8 w1_gpio_read_bit(void *data)
  64 {
  65         struct w1_gpio_platform_data *pdata = data;
  66
  67         return gpio_get_value(pdata->pin) ? 1 : 0;
  68 }
  69
  70 #if defined(CONFIG_OF)
  71 static struct of_device_id w1_gpio_dt_ids[] = {
  72         { .compatible = "w1-gpio" },
  73         {}
  74 };
  75 MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
  76 #endif
  77
  78 static int w1_gpio_probe_dt(struct platform_device *pdev)
  79 {
  80         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
  81         struct device_node *np = pdev->dev.of_node;
  82         int gpio;
  83
  84         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
  85         if (!pdata)
  86                 return -ENOMEM;
  87
  88         if (of_get_property(np, "linux,open-drain", NULL))
  89                 pdata->is_open_drain = 1;
  90
  91         gpio = of_get_gpio(np, 0);
  92         if (gpio < 0)
  93                 return gpio;
  94         pdata->pin = gpio;
  95
  96         pdata->ext_pullup_enable_pin = of_get_gpio(np, 1);
  97         pdev->dev.platform_data = pdata;
  98
  99         return 0;
 100 }
 101
 102 static int w1_gpio_probe(struct platform_device *pdev)
 103 {
 104         struct w1_bus_master *master;
 105         struct w1_gpio_platform_data *pdata;
 106         int err;
 107
 108         if (of_have_populated_dt()) {
 109                 err = w1_gpio_probe_dt(pdev);
 110                 if (err < 0) {
 111                         dev_err(&pdev->dev, "Failed to parse DT\n");
 112                         return err;
 113                 }
 114         }
 115
 116         pdata = dev_get_platdata(&pdev->dev);
 117
 118         if (!pdata) {
 119                 dev_err(&pdev->dev, "No configuration data\n");
 120                 return -ENXIO;
 121         }
 122
 123         master = devm_kzalloc(&pdev->dev, sizeof(struct w1_bus_master),
 124                         GFP_KERNEL);
 125         if (!master) {
 126                 dev_err(&pdev->dev, "Out of memory\n");
 127                 return -ENOMEM;
 128         }
 129
 130         err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
 131         if (err) {
 132                 dev_err(&pdev->dev, "gpio_request (pin) failed\n");
 133                 return err;
 134         }
 135
 136         if (gpio_is_valid(pdata->ext_pullup_enable_pin)) {
 137                 err = devm_gpio_request_one(&pdev->dev,
 138                                 pdata->ext_pullup_enable_pin, GPIOF_INIT_LOW,
 139                                 "w1 pullup");
 140                 if (err < 0) {
 141                         dev_err(&pdev->dev, "gpio_request_one "
 142                                         "(ext_pullup_enable_pin) failed\n");
 143                         return err;
 144                 }
 145         }
 146
 147         master->data = pdata;
 148         master->read_bit = w1_gpio_read_bit;
 149
 150         if (pdata->is_open_drain) {
 151                 gpio_direction_output(pdata->pin, 1);
 152                 master->write_bit = w1_gpio_write_bit_val;
 153         } else {
 154                 gpio_direction_input(pdata->pin);
 155                 master->write_bit = w1_gpio_write_bit_dir;
 156                 master->set_pullup = w1_gpio_set_pullup;
 157         }
 158
 159         err = w1_add_master_device(master);
 160         if (err) {
 161                 dev_err(&pdev->dev, "w1_add_master device failed\n");
 162                 return err;
 163         }
 164
 165         if (pdata->enable_external_pullup)
 166                 pdata->enable_external_pullup(1);
 167
 168         if (gpio_is_valid(pdata->ext_pullup_enable_pin))
 169                 gpio_set_value(pdata->ext_pullup_enable_pin, 1);
 170
 171         platform_set_drvdata(pdev, master);
 172
 173         return 0;
 174 }
 175
 176 static int w1_gpio_remove(struct platform_device *pdev)
 177 {
 178         struct w1_bus_master *master = platform_get_drvdata(pdev);
 179         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
 180
 181         if (pdata->enable_external_pullup)
 182                 pdata->enable_external_pullup(0);
 183
 184         if (gpio_is_valid(pdata->ext_pullup_enable_pin))
 185                 gpio_set_value(pdata->ext_pullup_enable_pin, 0);
 186
 187         w1_remove_master_device(master);
 188
 189         return 0;
 190 }
 191
 192 #ifdef CONFIG_PM
 193
 194 static int w1_gpio_suspend(struct platform_device *pdev, pm_message_t state)
 195 {
 196         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
 197
 198         if (pdata->enable_external_pullup)
 199                 pdata->enable_external_pullup(0);
 200
 201         return 0;
 202 }
 203
 204 static int w1_gpio_resume(struct platform_device *pdev)
 205 {
 206         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
 207
 208         if (pdata->enable_external_pullup)
 209                 pdata->enable_external_pullup(1);
 210
 211         return 0;
 212 }
 213
 214 #else
 215 #define w1_gpio_suspend NULL
 216 #define w1_gpio_resume  NULL
 217 #endif
 218
 219 static struct platform_driver w1_gpio_driver = {
 220         .driver = {
 221                 .name   = "w1-gpio",
 222                 .owner  = THIS_MODULE,
 223                 .of_match_table = of_match_ptr(w1_gpio_dt_ids),
 224         },
 225         .probe = w1_gpio_probe,
 226         .remove = w1_gpio_remove,
 227         .suspend = w1_gpio_suspend,
 228         .resume = w1_gpio_resume,
 229 };
 230
 231 module_platform_driver(w1_gpio_driver);
 232
 233 MODULE_DESCRIPTION("GPIO w1 bus master driver");
 234 MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
 235 MODULE_LICENSE("GPL");